So the question became: Who was the source of the leak, which
revealed a secret UK surveillance base in the Middle
East?

One theory, advanced first by journalist and former intelligence analyst Joshua
Foust, is that the people originally in control of their
cache of source material — journalists Laura Poitras
and Glenn Greenwald, Greenwald's partner David
Miranda, and Snowden — have lost control of that material.

In a brief email to Business Insider, Greenwald rejected those
suggestions, in part. He didn't give a definitive "no," but he
suggested it would be "highly unlikely."

"Everything is a 'possibility,' but I think it's highly
unlikely for multiple reasons," Greenwald said in the
email.

One of those reasons is that Greenwald and Snowden believe that the
UK government had a hand in the leak to The Independent. Snowden
asserted in a statement to Greenwald that the government did so
to advance the notion that Snowden's leaks have been
harmful.

That reasoning, though, is exactly why Foust thinks it's unlikely
the UK government played a part in the leak. Why would the
government intentionally harm itself to discredit Snowden, who
has "has already leaked and therefore damaged other
programs?"

More likely, Foust said, is that the web of information-holders
could have spiraled out of control. In addition to Poitras,
Greenwald, and The Washington Post's Barton Gellman, Snowden also
provided information to the German news magazine Der Spiegel and
the South China Morning Post. Snowden has previously denied he provided any
information to Russian and Chinese governments.

For his part, the editor of The Independent shot back at
Greenwald and Snowden's theory in a tweet Friday:

For the record: The Independent was not leaked or ‘duped’ into
publishing today's front page story by the Government. @ggreenwald